1994 525i Oil Usage

Hey all,
Been lurking out here for a couple of years and found much good advice. This is my first post.
Bought a 1994 525i with 205,000 miles on it two and a half years ago. I have added approx 15,000 miles.

The owner told me that it used some oil (approx 1qt every 3,000 miles). My previous vehicle (94 Mazda pickup) used about the same. Upon purchase, I discovered it used a bit more than that (approx 1qt every 700 miles). Found a local mechanic that specializes in BMWs. He replaced the valve cover gaskets and usage was then about a quart every 1500 miles for a short period of time. Usage has be increasing again and now to about a quart every 600 miles. I can find no evidence of leakage on the pavement and it does not smoke as if burning oil. Not sure what direction to follow. Have not had it back to the shop yet. Spoke with a friend that deals in BMWs and he indicated that it was not an uncommon problem and it had to do the the oil venting and it was burning, but not enough to produce smoke. To add to the issue, it uses more when driving on the interstate than around town. It is a 300 mile round trip from here to Atlanta and it will use a quart on that trip.

I just bought a 2006 Mini Cooper S and have not decided yet rather I am going to keep the BMW. Not sure why I bought the Mini other than I have always wanted one and it is fun a heck to drive. I live in a condo complex and have only one parking space, so I am not sure where I would keep a second car. Both my mother and my sister are interested in it, but I do not want to sell it to them if there is an inherent issue. I love this BMW and would love to keep it in the family. Most comfortable car I have ridden in and handles great.

Might very well be valve guides, unless the rings have gone. You need to have a compression and leak-down test performed to figure out which it is. A stuck EGR valve is also a possibility.

If the consumption were twice that at 1200 miles, I wouldn't worry. That was what our '91 525i (which was also alpine white) did from around 100K until 200K (when when it was "totalled" in a minor fender-bender.) But what you're experiencing is quite a lot.

Just because there's no oil on the ground doesn't mean it doesn't have an oil leak. Have a mechanic check the engine over for leaks. Could be getting on the exhaust and cooking on or coating the underside of the car but you should be able to smell something with the interior/vent fan on. Also have someone follow you down the road up to about 80mph and see if they notice smoke. Often it won't show up at idle or when blipping the throttle.

Thanks for the advice.
I have been wondering about a compression test. Not familiar with the leak down test. I will have to look that one up.
The only time I have smelled anything was when accelerating onto the interstate. I did have someone follow me but at 45mph and not 80.
I guess the long and the short is a visit to the mechanic.
Thanks a bunch for your help!